Drum cam having axial cushioning means



April 18, 1967 B. SCHROFF 3,314,302

DRUM CAM HAVING AXIAL CUSHIONING MEANS Filed June 11, 1965 IN VENTOR BERNHRRD SCHROFF United States Patent 3,314,302 DRUM CAM HAVING AXIAL CUSHIONING MEANS Bernhard Schrotf, Zollikerberg, Zurich, Switzerland, assiguor to Maschinenfabrik Scharer, Erleubach, Switzerland Filed June 11, 1965, Ser. No. 463,307 Claims priority, application Switzerland, July 10, 1964 9,085/ 64 2 Claims. (Cl. 74567) The present invention has reference to an improved drum cam for use with a roller follower for a winder or winding machine.

A drum cam can be used in winding machines for the to-and-fro movement of a yarn guide. With high speed winding machines due to delay and acceleration of the yarn guide and the element moving back and forth for displacing the yarn guide there occur pronounced oscillations or vibrations and at the points of reversal of the yarn guide and the cam follower there occur disturbing shocks or jolts. The vibrations or shocks are that much larger the quicker the machine operates. Additionally, due to these vibrations and shocks the cam is strongly subjected to load and large wear.

Accordingly, it is a primary object of the present invention to overcome these disadvantages and to dampen the vibrations and shocks or at least to mollify their deleterious effects upon the cam.

Another important object of the present invention relates to the provision of an improved drum cam operating with a cam roller wherein the harmful vibrations and impacts to which the drum cam is subjected during operation are effectively dampened.

In order to implement these and still further objects of the invention the drum eccentric designed according to the teachings of the present invention incorporates a cylinder provided with a cam groove between the opposite front ends of such cylinder. Plate means are provided for supporting this cylinder and a cushion, preferably an air cushion, is arranged in operable association with the plate means and effective in the axial direction of the aforesaid cylinder. For instance, at the respective front end of the cylinder and at the confronting portion of the plate means there can be provided a respective annular groove which is substantially semi-circular in cross-section and in which a hose filled with air serving as pneumatic cushioning means can be inserted.

Other features, objects and advantages of the invention will become apparent by reference to the following detailed description and drawing wherein the single figure depicts a cross-sectional view of a preferred embodiment of inventive drum cam arrangement.

Turning attention now to the drawing it will be ap preciated that there is depicted a cross-sectional view of my drum cam D designed according to the teachings of the present invention. This drum cam D incorporates a body member, in this instance a hollow cylinder provided between opposed ends 10a with a cam groove 11 in which a non-illustrated roller follower carries out in known manner a to-and-fro movement in the axial direction of the aforesaid cylinder 10 during each rot-ation of drum cam D. Cylinder 10 is supported by two end plates or disks 12 and 13 provided with hubs 14 and 15 respectively. These plates 12 and 13 are pushed by means of their hubs 14 and 15 onto a non-illustrated shaft.

Both plates 12 and 13 are shown here to be held together by a number of screw bolts 16, only one of which is visible in the drawing. It will be observed that at each end of the screw bolt 16 and between both of the plates 12 and 13 there is provided a respective nut 17 3,314,302 Patented Apr. 18,1967

and a further respective nut 18 is located at the opposite face of each plate 12 and 13. The nuts 17 prevent the plates 12 and 13 from being pressed against the confronting frontal end or face 10a of the cylinder 10 when upon the common shaft'onto which they are "pushed by connecting such for instance with the aid of a set screw 20 or equivalent expedient shown provided at the hub 14 for example.

It will further be appreciated that the cylinder 10 is prevented from carrying out radial displacement by means of a respective inwardly directed shoulder 19 provided at each of these plates 12 and 13. At each frontal face or end 10a of the cylinder 10 there is provided, according to the teachings of the invention, an annular groove or recess 21 which in cross-section is substantially semicircular shaped. Furthermore, at the respective confronting portion 12a and 13a of the plates 12 and 13 there is analagously provided a respective annular groove or recess 22 also of substantially semi-circular cross-sectional configuration. Both of the confronting annular grooves 21 and 22 collectively form a ring-shaped i.e. in crosssection round, channel 25 into which a hose 23 filled with a dampening fluid medium, e.g. air, is inserted. As previously mentioned, a certain clearance or play is provided between the frontal face or end 10a of the cylinder 10 and the corresponding confronting portion or frontal face 12a and 13a of the plates 12 and 13, whereas the hose 23 contacts the walls of both associated grooves 21 and 22. Thus, when the cylinder 10 is axially displaced, the hose 23 arranged at the end of the drum cam D towards which the cylinder 10 is moving, is initially compressed before the corresponding frontal face 10a of the cylinder 10 bears against the associated plate 12 or 13. In this manner, the cylinder 10 is axially cushioned in both directions by means of the hoses 23, in other words to both the left and right of the drawing.

Naturally, such a pneumatic cushioning or shock absorbing means can also be provided for cam disks, the cushioning must be correspondingly effective in radial direction with respect to the shaft upon which the cam disk or disks are seated.

Dampening of the oscillation or vibrations of the toand-fro moving element driving the yarn guide of a winding machine takes place with the inventive pneumatic cushioning arrangement in the following manner: At the reversal points of the non-illustrated eccentric roller travelling in the cam groove 11 of the cylinder 10, the reaction force generated by delaying and accelerating the aforesaid roller strives to compress the relevant hose so that the air inside such hose is also compressed while the other hose at the other end of the cylinder 10 expauds and the therein contained air can correspondingly expand. Due to this compression and expansion of the air the oscillation or vibration energy is converted into heat. Naturally, a certain amount of heat results due to deformation of the rubber hoses 23 and the possible friction betwen hose and associated circular channel 25. Due to the conversion of the vibrational energy into heat there can be brought about an effective dampening of the oscillations and impacts at high speed Winding machines, so that wear of the cylinder 10 is considerably prevented.

While there is shown and described present preferred embodiment of the invention it is to be distinctly understoodthat the invention is not limited thereto but may be otherwise variously embodied and practised within the scope of the following claims.

What is claimed is:

1. A drum cam for winding machines comprising a cylinder having oppositely disposed frontal ends and a cam groove defined around the exterior of said cylinder between said frontal ends for receiving a follower, a plate member for supporting said cylinder arranged in confronting relationship to each frontal end of said cylinder, each said plate member and the associated confronting frontal end of said cylinder being provided with a respective annular groove of substantially semi-circular shape configuration in cross section, a hose member inserted in each of said annular grooves at each frontal end of said cylinder and the confronting associated plate member,

said hose member being filled with a dampening fluid medium providing cushioning means effective in an axial direction of said cylinder.

2. Drum eccentric arrangement for winding machines according to claim 1 wherein said dampening fluid medium is air.

References Cited by the Examiner UNITED STATES PATENTS 1,387,855 8/1921 Lippitt 74-567 2,167,705 8/1939 Batten 74-574 3,089,657 5/1963 Chaussy 74567 3,103,083 9/1963 Seeger 220-46 3,159,884 12/1964 Hankey 220-46 FRED C. MATTERN, JR., Primary Examiner. W. S. RATLIFF, Assistant Examiner. 

1. A DRUM CAM FOR WINDING MACHINES COMPRISING A CYLINDER HAVING OPPOSITELY DISPOSED FRONTAL ENDS AND A CAM GROOVE DEFINED AROUND THE EXTERIOR OF SAID CYLINDER BETWEEN SAID FRONTAL ENDS FOR RECEIVING A FOLLOWER, A PLATE MEMBER FOR SUPPORTING SAID CYLINDER ARRANGED IN CONFRONTING RELATIONSHIP TO EACH FRONTAL END OF SAID CYLINDER, EACH SAID PLATE MEMBER AND THE ASSOCIATED CONFRONTING FRONTAL END OF SAID CYLINDER BEING PROVIDED WITH A RESPECTIVE ANNULAR GROOVE OF SUBSTANTIALLY SEMI-CIRCULAR SHAPE CONFIGURATION IN CROSS SECTION, A HOSE MEMBER INSERTED IN EACH OF SAID ANNULAR GROOVES AT EACH FRONTAL END OF SAID CYLINDER AND THE CONFRONTING ASSOCIATED PLATE MEMBER, SAID HOSE MEMBER BEING FILLED WITH A DAMPENING FLUID MEDIUM PROVIDING CUSHIONING MEANS EFFECTIVE IN AN AXIAL DIRECTION OF SAID CYLINDER. 